01465nas a2200193 4500008004100000022001400041245011700055210006900172260000800241300001400249490000700263520077500270100002201045700002801067700001401095700001801109700002001127856012401147 2019 eng d a2041-652000aNickel-catalyzed C-H alkylation of indoles with unactivated alkyl chlorides: evidence of a Ni(i)/Ni(iii) pathway0 aNickelcatalyzed CH alkylation of indoles with unactivated alkyl  cNOV a9493-95000 v103 a

A mild and efficient nickel-catalyzed method for the coupling of unactivated primary and secondary alkyl chlorides with the C-H bond of indoles and pyrroles is described which demonstrates a high level of chemo and regioselectivity. The reaction tolerates numerous functionalities, such as halide, alkenyl, alkynyl, ether, thioether, furanyl, pyrrolyl, indolyl and carbazolyl groups including acyclic and cyclic alkyls under the reaction conditions. Mechanistic investigation highlights that the alkylation proceeds through a single-electron transfer (SET) process with Ni(i)-species being the active catalyst. Overall, the alkylation follows a Ni(i)/Ni(iii) pathway involving the rate-influencing two-step single-electron oxidative addition of alkyl chlorides.

1 aPandey, Dilip, K.1 aAnkade, Shidheshwar, B.1 aAli, Abad1 aVinod, C., P.1 aPunji, Benudhar uhttp://library.ncl.res.in/content/nickel-catalyzed-c-h-alkylation-indoles-unactivated-alkyl-chlorides-evidence-niiniiii01868nas a2200241 4500008004100000022001400041245013600055210006900191260000800260300001200268490000600280520105500286653001701341653001901358653001201377653001401389653001101403653002901414100002201443700001801465700002001483856012301503 2019 eng d a2155-543500aNickel-catalyzed straightforward and regioselective C-H alkenylation of indoles with alkenyl bromides: scope and mechanistic aspect0 aNickelcatalyzed straightforward and regioselective CH alkenylati cJAN a431-4410 v93 a

Nickel-catalyzed regioselective C-H bond alkenylation of indoles and related heteroarenes with alkenyl bromides is accomplished under relatively mild conditions. This method allows the straightforward synthesis of C-2 alkenylated indoles employing an air-stable and well-defined nickel catalyst, (bpy)NiBr2, providing a solution to the limitations associated with hydroindolation and oxidative alkenylation. The reaction conceded the coupling of indole derivatives with various alkenyl bromides, such as aromatic and heteroaromatics, alpha- and beta-substituted as well as exo- and endo-cyclic alkenyl compounds. An extensive mechanistic investigation, including controlled study, reactivity experiments, kinetics and labeling studies, and EPR and XPS analyses, highlights that the alkenylation proceeds through a single-electron transfer process comprising an odd-electron oxidative addition of alkenyl bromide. Furthermore, the alkenylation operates via a probable Ni(I)/Ni(III) pathway involving the rate-limiting C-H nickelation of indole.

10aalkenylation10aC-H activation10aindoles10aMechanism10aNickel10asingle-electron transfer1 aJagtap, Rahul, A.1 aVinod, C., P.1 aPunji, Benudhar uhttp://library.ncl.res.in/content/nickel-catalyzed-straightforward-and-regioselective-c-h-alkenylation-indoles-alkenyl02274nas a2200253 4500008004100000022001400041245016000055210006900215260000800284300001600292490000700308520136500315653002001680653002201700653002701722653001901749653002601768100001601794700001901810700002101829700001801850700002201868856013001890 2020 eng d a1944-824400aNanocrystalline Ag3PO4 for sunlight- and ambient air-driven oxidation of amines: high photocatalytic efficiency and a facile catalyst regeneration strategy0 aNanocrystalline Ag3PO4 for sunlight and ambient airdriven oxidat cJUL a29324-293340 v123 a

Selective oxidation of amines to imines using sunlight as clean and renewable energy source is an important but challenging chemical transformation because of high reactivity of the generated imines and lack of visible light-responsive materials with high conversion rates. In addition, oxygen gas has to be purged in the reaction mixture in order to increase the reaction efficiency which, in itself, is an energy-consuming process. Herein, we report, for the first time, the use of Ag3PO4 as an excellent photocatalyst for the oxidative coupling of benzyl amines induced by ambient air in the absence of any external source of molecular oxygen at room temperature. The conversion efficiency for the selective oxidation of benzyl amine was found to be greater than 95% with a selectivity of >99% after 40 min of light irradiation indicating an exceptionally high conversion efficiency with a rate constant of 0.002 min(-1), a turnover frequency of 57 h(-1), and a quantum yield of 19%, considering all of the absorbed photons. Ag3PO4, however, is known for its poor photostability owing to a positive conduction band position and a favorable reduction potential to metallic silver. Therefore, we further employed a simple catalyst regeneration strategy and showed that the catalyst can be recycled with negligible loss of activity and selectivity.

10aamine oxidation10aenergy harvesting10ananocrystalline Ag3PO410aPhotocatalysis10aregeneration strategy1 aGarg, Reeya1 aMondal, Sanjit1 aSahoo, Lipipuspa1 aVinod, C., P.1 aGautam, Ujjal, K. uhttp://library.ncl.res.in/content/nanocrystalline-ag3po4-sunlight-and-ambient-air-driven-oxidation-amines-high-photocatalytic